Modulation of the Pacific Decadal Oscillation on the summer precipitation over East China: a comparison of observations to 600-years control run of Bergen Climate Model   总被引：2，自引：0，他引：2  

Lei?YuEmail author  Tore?Furevik  Odd?Helge?Otter?  Yongqi?Gao 《Climate Dynamics》2015,44(1-2):475-494

Observations show that the summer precipitation over East China often goes through decadal variations of opposite sign over North China and the Yangtze River valley (YRV), such as the “southern flood and northern drought” pattern that occurred during the late 1970s–1990s. In this study it is shown that a modulation of the Pacific Decadal Oscillation (PDO) on the summer precipitation pattern over East China during the last century is partly responsible for this characteristic precipitation pattern. During positive PDO phases, the warm winter sea surface temperatures (SSTs) in the eastern subtropical Pacific along the western coast of North American propagate to the tropics in the following summer due to weakened oceanic meridional circulation and the existence of a coupled wind–evaporation–SST feedback mechanism, resulting in a warming in the eastern tropical Pacific Ocean (5°N–20°N, 160°W–120°W) in summer. This in turn causes a zonal anomalous circulation over the subtropical–tropical Pacific Ocean that induces a strengthened western Pacific subtropical high (WPSH) and thus more moisture over the YRV region. The end result of these events is that the summer precipitation is increased over the YRV region while it is decreased over North China. The suggested mechanism is found both in the observations and in a 600-years fully coupled pre-industrial multi-century control simulations with Bergen Climate Model. The intensification of the WPSH due to the warming in the eastern tropical Pacific Ocean was also examined in idealized SSTA-forced AGCM experiments.  相似文献   

Export of Greenland Sea water across the Mohn Ridge induced by summer storms     

Xusiyang Shen  Jinping Zhao  Xiaoyu Wang  Tore Hattermann  Wenqi Shi  Long Lin  Ping Chen 《海洋学报(英文版)》2023,42(2):17-28

The Mohn Ridge separates the Greenland Sea and the Lofoten Basin. Previous studies identified the export across the Mohn Ridge(EMR) from the Greenland Basin into the Lofoten Basin using water mass analysis and the tracer diffusion method, but there is still lack of direct current measurements. A surface mooring with four current meters was deployed on the Mohn Ridge from June 5 to June 18 in 2015, when three cyclones passed in the adjacent area. In the absence of cyclones, the flow on the Mohn R...  相似文献   

The day to night absorption ratio in auroral zone riometer measurements   总被引：1，自引：0，他引：1  

Richard J. Armstrong  F.Tom Berkey  Tore Melbye 《Planetary and Space Science》1977,25(12):1193-1198

The day to night ratio in ionospheric radio wave absorption has been studied for College, Alaska using a narrow beam riometer array and computer assisted programming of the data. For the period of 6 November 1967 to 17 April 1968 no significant departure from a ratio of unity was found.  相似文献   

A pseudospectral approach to the McWhorter and Sunada equation for two-phase flow in porous media with capillary pressure     

Tore I. Bjørnarå  Simon A. Mathias 《Computational Geosciences》2013,17(6):889-897

  相似文献   

A submarine landslide complex affecting the Jan Mayen Ridge, Norwegian–Greenland Sea: slide-scar morphology and processes of sediment evacuation     

Jan S. Laberg  Kiichiro Kawamura  Hilde Amundsen  Nicole Baeten  Matthias Forwick  Tom A. Rydningen  Tore O. Vorren 《Geo-Marine Letters》2014,34(1):51-58

Swath-bathymetry data and 2D multichannel seismics reveal for the first time an up to ~60 km wide amphitheater-shaped slide scar on the eastern flank of the Jan Mayen Ridge, a micro-continent in the Norwegian–Greenland Sea. The scar opens southeastward where it continues as a narrower, topographically controlled translational area. It includes secondary scars, as well as channels and escarpments. Based on the identification of secondary scars, the slide is classified as a slide complex and the total volume of missing sediments was estimated at ~60 km³. From the overall shape of the scar, the upslope widening from a bottleneck- or channel-like bypass-area, the failure is inferred to have had a retrogressive development. The absence of ridges, slabs and sediment blocks indicates that the failed sediments have been evacuated entirely. The smaller channels were formed from single or repetitive smaller flows post-dating the large failure events.  相似文献   

Sources of surface water for the Soncor ecosystem,Salar de Atacama basin,northern Chile     

C. Ortiz  R. Aravena  E. Briones  F. Suárez  C. Tore  J.F. Muñoz 《水文科学杂志》2013,58(2):336-350

Abstract

The Salar de Atacama is located in the most arid desert in the world. Despite its extreme conditions, it has many ecosystems of high ecological value. The Soncor ecosystem, a sequence of lagoons, is the most important environment of the region as it acts as the centre for the breeding of the Andean Flamingo. This salt flat also contains significant mining deposits and is an important water source for the region. Freshwater and brine—enriched in lithium and potassium—are being pumped from the aquifers near to the Soncor ecosystem, which has so far not been greatly affected by this groundwater extraction. However, there is a potential risk that future anthropogenic effects may disturb this fragile environment. The objective of this study is to determine the origin of the water sources of the Soncor ecosystem so as to adequately manage its water resources. Three hypotheses previously proposed in the technical literature were investigated in order to determine proactive actions to protect this fragile ecosystem. The study utilized classic hydrogeological techniques, such as the construction of stratigraphic profiles, piezometric maps and stream gauging, combined with less-common isotopic techniques, such as the ⁸⁷Sr/⁸⁶Sr ratio. The results confirmed the hypothesis that the origins of the water sources are associated with groundwater inputs coming from the east side of the salt flat, in the north of the basin.

Editor Z.W. Kundzewicz; Associate editor M. Acreman

Citation Ortiz, C., Aravena, R., Briones, E., Suárez, F., Tore, C., and Muñoz, J.F., 2014. Sources of surface water for the Soncor ecosystem, Salar de Atacama basin, northern Chile. Hydrological Sciences Journal, 59 (2), 336–350.  相似文献   

Anomalous strontium and lead isotope signatures in the off-rift Öræfajökull central volcano in south-east Iceland: Evidence for enriched endmember(s) of the Iceland mantle plume?     

Tore Prestvik  Steven Goldberg  Haraldur Karlsson  Karl Grnvold 《Earth and Planetary Science Letters》2001,190(3-4):211-220

The currently active off-rift central volcano Öræfajökull in south-east Iceland sits unconformably on much older (10–12 Ma) and eroded crust. The composition of recent volcanics ranges from basalt to rhyolite, but the series is more sodic alkaline than the common rift zone tholeiitic suites. In this study we present Sr, Nd, Pb and O isotopic data for a suite of Öræfajökull samples. The complete suite shows typical mantle values for oxygen isotopes. The ⁸⁷Sr/⁸⁶Sr ratios (average of 15 SAMPLES=0.703702) of the modern Öræfajökull rocks (basalts as well as rhyolites) are much higher than observed so far for any other Icelandic rocks. The ¹⁴³Nd/¹⁴⁴Nd ratios (average=0.512947; n=15) are lower than for rift rocks, but similar to rocks of the off-rift Snæfellsnes volcanic zone. Furthermore, the Öræfajökull rocks are enriched in the ²⁰⁷Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb isotope ratios compared to Icelandic rift basalts. The enriched nature of the suite indicates that Öræfajökull samples a source component that has characteristics common with EM2 type mantle. Furthermore, it is concluded that the silicic rocks of Öræfajökull formed by fractional crystallization from mafic melts rather than by partial melting of older crust.  相似文献   

Empirical estimation of isostatic uplift using the lake-tilting method at lake Fegen and lake S?ven, southwestern Sweden     

Tore P?sse 《Mathematical Geology》1990,22(7):803-824

A nonuniform glacio-isostatic uplift results in differential uplift for different parts of a lake. If the lake outlet is situated in the area with the greatest rate of uplift, then the lake will be continuously transgressed. Ancient lake levels can be estimated by dating transgressed peat at different depths in such a lake. Two lakes in southwestern Sweden have been investigated by this method and the course of glacio-isostatic uplift has been determined empirically. The uplift can be expressed by an exponential function through the following formula

相似文献    59. Submerged terraces in the southwestern Barents Sea: origin and implications for the late Cenozoic geological history      Erland Lebesbye  Tore O. Vorren 《Marine Geology》1996,130(3-4):265-280 Based on high-resolution seismics, submerged terraces have been identified and mapped. They constitute two semi-continuous terrace zones that can be followed for up to about 350 km along the bank flanks, at more or less uniform depths of ca. 150 m and ca. 220 m, respectively. The features are interpreted as wave-cut platforms, and thus indicate a submergence of as much as 220 m after they formed. Several arguments suggest that they were probably not formed during glaciation maxima, but rather during interglacials or parts of glacials with restricted glaciation. Consequently, only a smaller part of their submergence may be due to glacial eustasy. A signigicant tectonic related subsidence is inferred. Relatively young ages are indicated since they are so lightly eroded by the Plio-Pleistocene ice sheets. A maximum age in the order of 0.8 Ma and a minimum age of 0.2 Ma is tentatively suggested. One implication is that subsidence rates for this part of the Barents Sea margin are in the range 0.2–0.9 m/kyr.  相似文献    60. Revisiting the influences of parent stock, temperature, and predation on the recruitment of the Northeast Arctic cod stock, 1930-1990      Pope  John; Large  Philip; Jakobsen  Tore 《ICES Journal of Marine Science》2001,58(5):967-972   相似文献    [首页] « 上一页 [1] [2] [3] [4] [5] 6 [7] [8] [9] 下一页 » 末  页»